import React from 'react';
class Hello extends React.Component {
    constructor(props) {
      super(props)
      this.state = {
        opacity: 1.0
      };
    }
   //生命周期
    componentDidMount() {
      this.timer = setInterval(function () {
        var opacity = this.state.opacity;
        opacity -= .05;
        if (opacity < 0.1) {
          opacity = 1.0;
        }
        this.setState({
          opacity: opacity
        });
      }.bind(this), 100);
    }

    render() {
      return (
        <div style={{opacity: this.state.opacity}}>
          Hello {this.props.name}
        </div>
      );
    }
  }

  export  default Hello